Variable-resistance coil.



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No. 890,737. PATENTED JUNE 1.6, 1908. A. WALLACE. VARIABLE RESISTANCE 0011 APPLICATION FILED AUG. 9, 1907,

No. 890,737. PATENT-ED JUNE 16, 1908'.

' H. A; WALLACE.

VARIABLE RESISTANCE COIL. APPLICATION FILED AUGQQ, 1907.

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" OFFICE.

HERBERT WALLACE, or new YORK, N. YlfAssienon TO THE Union SWITCH & SIGNAL \GOMPANY, OF 'SWISSVALE', PENNSYLVANIA, A GORPORATION or PENNSYLVANIA.-

VARIABLE-RESISTANCE coin. I

Specification of Letters Patent.

Patented June 1c, 1903.

Application filed August 9, 1907. Serial No. 387,896. v

' To all whom it may concern:

Be it knownthat I, HERBERT A. WALLACE, a citizen of the United. States, and resident'ot the borough of Manhattan, cityf-eounty, and State of New York, have invented certain new and useful Improvements in VariablevResistance Coils, of which the following is a specification.

This invention relates to variable resistance coils. H

T will describe a preferredembodiment of my invention and then point out the novel features in claims. v Figure 1 is a vertical section of my improved var iable resistance coil. Fig. 2 is a horizontal section. Fig. 3 is a diagram,- matic View showing the resistance in a railway track circuit.

A indicates a base of porcelain or other suitable insulating material and preferably haying a pocket or recess a in its lower side. A spool B of insulating material is supported on the base and surrounds a metal post 0 se cured to the base. As shown the post consists of a .rod or bolt which extends through the base and spool and is threaded at its upper end to receive a nut c which engages'a washer (Z resting on the upper end of the spool and thereby clamps the spool to the base. The spool B is provided with spiral grooves 11 to receive the windings of the coil D; One end of the coil is connected to a binding 0st E on the base and the other to the post 8 by being clamped between the nut c and washer d. The post C is metallically connected to another binding post F by metal strip A wire 10 leads from the binding post F to a track rail H and a wire 11 leads from the binding post E to the other track rail 1 and a battery 12 is included in the circuit.

G is the regulator and as shown consists of a U-shaped piece of spring metal, the arms of which are adapted to straddle the resistance coil and engage it on opposite sides. Preferably the arms are curved transversely at their lower ends to increase the area oi their contact with the resistance coil. The

arms (1 are metallically connected to the post' C and are movable 'on the coil. As shown they are connected to a nut 72. which screws on the u per threaded. portion of the post C and the atter will preferably be long enough to permit the arms 9 to. connect with any portion of the coil. A jam-nut imay also be employed. to'engage the nut h. The regulator will preferably be made of a metal havmg a'low resistance. Y

By adjusting the regulator up or down on the coil the resistance will be increased or diminished since the regulator will act as a low resistance shunt to the part of the resista ance coil above the point of contact of the arms 9 therewith. A

. in Fig. 3 I have illustrated a blockor'sec tion of a railway track in which the rails H and I are electrically connected to a relay K Y which may form a part of a signal operating mechanism. It is not necessary to illustrate this mechanism in detall as any of well known types maybe employed. The variable resistance is also included in the track circuit be tween the battery 12 and the relay K.

hile I have" illustrated my invention applied in a raihvaytraclt signaling circuit its application is not limited to such circuits.

I do not limit myscltto the details of construction illustrated. as other means may be employed for adjusting the regulator on the coil and other means may be employed for met-allically connecting the regulator with one of the circuit wires.

Haring described the invention. I claim: 1.. The combination with two wires lorming part of an electric -circuit. of a metal post connected to one of said wires and being threaded, a spool of insulating material sur+ 0n.the' spool and havin one terminal cennected to said post and the other terminal to the, other Wire, a metallic regulator having a threaded openingto receive the threaded portion of the post, arid said regulator also engaging the resistance Coil and a source of electnc supply mcluded m' the clrcmt.

IIiv vitness whereof I. have hereunto signed my name 1n the presence of two subscnbed Witnesses.

HERBERT A. WALLACE, Witnesses:-

GEO. E. CRUSE, H. A. HAMILTON. 

